Rationing of scarce vaccine supplies will likely be required when the next pandemic occurs, raising the questions about how to ration and upon what principles. Because influenza pandemics have differing mortality patterns, such as the 1918 pandemic's "W" shaped curve that effected healthy young adults, the particular pattern should inform rationing. Competing ethical principles for vaccine rationing are utilitarianism and egalitarianism. Vaccine manufacturers and essential healthcare workers can be justified with either principle. Utilitarian principles of choosing based on social worth or those in whom vaccination is most likely to medically succeed raise substantial justice issues. Egalitarian principles of medical neediness and random chance avoid justice concerns and are proposed. A framework that uses multiple principles to address influenza vaccine rationing in light of a shortage is recommended.